Inside the PlayStation 4: A balanced approach to building a game console

The RAM

There are two things you need to know about the PS4's memory: there's a ton of it, and it's fast. The PS4 comes with 8GB of GDDR5 RAM—this fast memory, which far outperforms the DDR3 in most of today's desktops and laptops, is generally only used in graphics cards, and the most common configurations still only use 1GB or 2GB (though higher capacities are available).

The PS3 had only 512MB of RAM, and that was split up into two 256MB chunks for the system memory and the graphics memory, respectively. In the PS4, the system and graphics RAM is unified—assuming that there's no artificial cap imposed on how much memory the CPU or GPU can access (and we have seen some rumors based on dev kits that the GPU can only access about 2GB of it, though that is unconfirmed at this point), this means that they can both grab as much memory as they want to be used in whatever way they need it.

Having a gob of fast memory is going to drive the console's price up a bit, but it should keep things moving briskly; on the gaming side, more memory will allow for the use of larger and more detailed textures, support for higher resolutions (hinting that a 4K future for some games isn't completely out of the question, though for my money it still seems unlikely), and more anti-aliasing. On the system side, it could help to reduce or eliminate mid-game load times—the console is going to be able to load much more into RAM at once, reducing the amount of time it has to spend hitting the hard drive or the optical disk to grab new data. It's a nice bit of future-proofing on Sony's part—even if developers aren't using the wealth of RAM available to them after years of working with 512MB, they'll definitely adjust rapidly.

The “secondary custom chip”

Enlarge/ We don't know that the PS4's "secondary custom chip" is ARM-based, but it's the only thing that makes sense.

Andrew Cunningham

We don't know much about the "secondary custom chip" in the PS4, but we do know what kinds of things the PS4 can do in the background without hitting the primary CPU and GPU: downloading updates and games, encoding and decoding video (as seen in the video sharing demo). Sony obviously wants this stuff to be quick, seamless, and invisible to the user, so it makes sense to offload it to another chip so that it doesn't slow down the console's rendering speed.

Sony has spent little time on the specifics of the extra chip (or chips) that accomplish these tasks, but it seems to us that the best bet is something ARM-based. It would be both easy and cheap to build an ARM processor with an integrated video encode and decode block that could handle these tasks using just a fraction of the power of the main hardware, and there are plenty of smaller companies building chips that fit this description for smart TVs and other embedded devices. There also exists the possibility that the video encoding and decoding could be integrated into the GPU without impacting game performance, though we see using an ARM chip for this as being more efficient from a power usage standpoint.

The storage

No real upgrades here; like the PS3, the PS4 will feature a Blu-Ray optical drive for discs and a mechanical hard drive for storage. We know that the Blu-Ray drive will run at speeds of 6X, up from 2X in the PS3, which should be a boon for gamers tired of waiting through lengthy game install processes, but we don't know anything about hard drive capacities yet.

This combination is pretty much the only one that makes sense. For a game console, solid state storage would drive the cost up too far relative to the benefits it would bestow—it's much more important to have room for all of those game installs and downloadable titles than it is for that content to load extremely quickly. It's possible that, as in the PS3, Sony will allow users to swap out their own hard drives in the PS4—if you want lightning-fast storage, that will be the way to get it.

One final thing that's worth noting: if the chipset in the PS4 is related to the AMD chipsets for desktops and laptops (and the presence of USB 3.0 in the console suggests that this is the case), it's probable that it will support SATA III transfer speeds (6.0Gb/s), up from the SATA I speeds in the PS3 (1.5Gb/s). The mechanical hard drive would still be something of a bottleneck here, but it should nevertheless provide a modest increase in data transfer speeds.

A balanced, well-considered console

The PS3 was, in many ways, the last and most ambitious example of the "old way" to design a gaming console—going with a custom-designed chip and hoping that developers, with enough time and effort, would be able to squeeze better and better visuals out of it as the lifespan of the console continued. The "old way" also dictated putting the biggest, fastest, most-expensive parts into that box that would safely fit, done both to make the graphics as impressive as possible on launch day and to lengthen the console's lifespan.

The PS4 (and, according to rumor, the next Xbox) reflects the way computing has changed since the last time new consoles were designed and released. Rather than using expensive custom-designed chips like Cell, it's using gently tweaked versions of off-the-rack PC parts from AMD. Rather than going for top-end chips, the console uses modern midrange parts that are faster than the consoles of yesteryear but don't approach the heights of a high-end PC.

This approach that the PS4 takes may disappoint those who value their polygon counts above all else, but to us it seems quite sensible—the PS4's hardware makes all the right compromises between price and performance, and the result will hopefully be something reliable with good power usage that doesn't cost 599 US dollars.

Andrew Cunningham / Andrew has a B.A. in Classics from Kenyon College and has over five years of experience in IT. His work has appeared on Charge Shot!!! and AnandTech, and he records a weekly book podcast called Overdue.